Hard disk drives are enclosures in which an inflexible platter coated with magnetic material is spun very rapidly. A magnetic read/write head "flies" only a few microns above the disk on an air cushion. To provide a hard disk drive having high efficiency, it is desirable to position the head as close to the disk as possible without touching it.
It has been found that particulate and gaseous contaminants act to reduce efficiency and longevity of hard disk drives. Common sources of contaminants in disk drives include leaks which may or may not be intentional, the manufacturing environment which can contain certain contaminants, and the materials incorporated into the disk drive which give off particulates and gases. It is of particular concern that organic vapors can be generated inside disk drive enclosures during normal operating conditions when, for example, the temperature exceeds 150.degree. F. Such temperatures can be achieved by simply leaving the computer in the trunk of a car on a hot day.
Recirculation filters have been used in hard disk drives for removing contaminates. Such filters have been effective for removing particulate contaminants. They are not, however, suitable for removing organic vapors since they do not have a capacity for permanently adsorbing organic vapors. To provide enhanced organic vapor removal, it has been proposed to include activated carbon in recirculation filters. Activated carbon in the form of granules or fiber can adsorb organic vapors. However, permeability of filters including such activated carbon is sacrificed. This results in an overall lower effectiveness of the filter.
Another problem is that activated carbon granules or fibers can escape filtering media and contaminate the hard disk drive enclosure. Previous attempts at controlling carbon migration include coating the edges of filters with resins or epoxies, and using additional material and/or mechanical clamps to seal the filter edges. Although these attempts help control carbon migration, it would be desirable to further reduce carbon migration.